U.S. patent number 4,576,590 [Application Number 06/566,649] was granted by the patent office on 1986-03-18 for intraluminal membrane oxygenator method for a tubular organ of the gastrointestinal tract.
Invention is credited to Richard G. Fiddian-Green.
United States Patent |
4,576,590 |
Fiddian-Green |
March 18, 1986 |
Intraluminal membrane oxygenator method for a tubular organ of the
gastrointestinal tract
Abstract
Apparatus and method for intraluminal membrane oxygenation of
internal organs. A catheter having a walled chamber is introduced
to dispose the chamber against the lumen of an internal organ. The
wall of the chamber is of a material which is freely permeable to
gases, such as oxygen and carbon dioxide, and poorly permeable to
liquid. Oxygen is introduced into the catheter and perfused through
the walled chamber. Oxygen passes through the wall of the chamber
to the organ while carbon dioxide from the organ passes through the
wall of the chamber.
Inventors: |
Fiddian-Green; Richard G. (Ann
Arbor, MI) |
Family
ID: |
24263809 |
Appl.
No.: |
06/566,649 |
Filed: |
December 29, 1983 |
Current U.S.
Class: |
604/26; 422/45;
604/500; 604/915; 604/96.01 |
Current CPC
Class: |
A61M
1/1678 (20130101); A61M 25/0127 (20130101); A61M
25/10 (20130101); A61M 1/1698 (20130101); A61M
2202/0208 (20130101); A61M 2202/0225 (20130101); A61M
2210/106 (20130101); A61M 2202/0208 (20130101); A61M
2202/0007 (20130101); A61M 2202/0225 (20130101); A61M
2202/0014 (20130101) |
Current International
Class: |
A61M
25/01 (20060101); A61M 25/10 (20060101); A61M
1/16 (20060101); A61M 025/00 (); A61M 037/00 () |
Field of
Search: |
;128/632,635
;606/24-26,27-29,43-45,51-54,96-103 ;3/1 ;422/45 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Truluck; Dalton L.
Attorney, Agent or Firm: Stephenson & Boller
Claims
What is claimed is:
1. A method for intraluminal membrane oxygenation of a tubular
internal organ of the gastrointestinal tract independently of the
vascular blood supply to the organ which comprises introducing a
catheter having a closed cylindrical walled chamber on a tube into
the organ so as to dispose the wall of the chamber in contact with
and against the lumen of the organ, said tube having an entrance to
and an exit from said chamber which are disposed axially spaced
apart along the length of the catheter, the wall of said chamber
comprising a material which is freely permeable to gas but poorly
permeable to liquid, perfusing the interior of the chamber via said
tube with oxygen to create a pressure gradient between the chamber
and the lumen of the organ so as to cause oxygen to diffuse through
the wall of the chamber to the lumen of the organ by introducing
oxygen into the tube at an external inlet, conducting the oxygen
through the tube and into the chamber, thence axially through the
chamber along the wall thereof, and thence from the chamber through
the tube to an external outlet, and continuing the perfusion step
for a sufficient time to conduct the oxygenation procedure.
2. A method as set forth in claim 1 in which oxygen is carried by a
fluid and introduced into the catheter via a pumping mechanism
connected with the tube.
3. A method as set forth in claim 2 in which the fluid is provided
with blood or a blood substitute to enhance the oxygen bearing
capacity of the fluid.
4. A method as set forth in claim 1 in which a vasodialator is also
introduced via the catheter to enhance local oxygenation.
5. A method as set forth in claim 1 in which carbon dioxide which
diffuses from the lumen of the organ through the wall of the
chamber is conveyed with returning flow passing from the chamber
through the tube.
6. A method as set forth in claim 1 in which oxygen is introduced
at a PO.sub.2 of about 760 mm.Hg.
Description
BACKGROUND AND SUMMARY OF THE INVENTION
This invention relates to medical treatment apparatus and methods
and more specifically is concerned with an intraluminal membrane
oxygenator for use in sustaining vitality of any organ in the
gastrointestinal tract.
The nature of human anatomy is such that each individual organ's
vitality is sustained by the circulation of blood through the
organ's vascular system. Each organ's vascular system is of course
a part of the body's larger cardio-vascular system.
For any of various reasons the circulation, and hence oxygen
delivery, to any given organ may become insufficient to sustain the
full vitality of that organ. For example, partial occlusion of an
artery may reduce blood flow to a point where the oxygen supply is
insufficient. An occlusion, whether full or partial, may be due
entirely to naturally occurring phenomenon or it may be in
consequence of certain procedures. Regardless of the cause, reduced
oxygen delivery can have potentially devastating effects on a
patient.
As another example, surgical procedures, possibly not even directly
related to a particular organ, may have an effect on the organ. For
instance, in the case of certain vascular surgery procedures, it
may be necessary to interrupt the blood flow to a given organ or
organs during the course of procedures. External blood pumps may be
used to supply the organ or organs during these procedures or else
the procedures must be performed with sufficient rapidity that the
temporary interruption of circulation to an organ will not produce
grave consequences.
The present invention is directed to a novel apparatus and
procedure for sustaining vitality of an internal organ in
situations such as these, particularly with reference to
gastrointestinal organs. With the present invention it is
unnecessary to utilize external devices, such as blood pumps, in
association with the vascular system. The present invention offers
a procedure and apparatus which can be used at any desired time,
for example, pre-operatively, during an operation, or
postoperatively.
One important advantage over prior techniques and apparatus is that
the invention does not directly involve the cardio-vascular system.
Rather, the invention contemplates the introduction of a catheter
into an organ of interest with vitality-sustaining oxygen being
introduced through the catheter. The catheter comprises a tube
having a walled chamber at one end. The catheter is introduced to
dispose the chamber against the lumen of the organ of interest. The
material of the chamber is one which is freely permeable to gas but
poorly permeable to liquid. The tube contains a conduit for
delivering fluid to the chamber. Oxygen is perfused through the
chamber via the tube from an external source. The external source
may comprise any suitable means to create an oxygen partial
pressure gradient between the interior of the chamber and the lumen
of the organ whereby oxygen can diffuse through the wall of the
chamber and into the organ. Carbon dioxide gas generated by the
organ can also diffuse through the wall of the chamber to be
conveyed back through the tube for removal. The chamber and tube
are so constructed and arranged as to create an axial flow along
the interior of the wall of the chamber along substantially the
full length of the chamber. This promotes the maximum area
availability for delivering oxygen to an organ, particularly in the
case where the organ is in the gastrointestinal tract. The diameter
of the chamber is less than that of the organ so that the catheter
does not block passage through the organ. The invention also
contemplates the use of agents such as the use of a vasodialator to
enhance oxygenation locally and the use of blood and/or blood
substitutes for oxygen-bearing purposes.
The foregoing features, advantages and benefits of the invention,
along with additional ones, will be seen in the ensuing description
and claims which should be considered in conjunction with the
accompanying drawings. The drawings disclose a preferred embodiment
of the invention according to the best mode contemplated at the
present time in carrying out the invention.
BRIEF DESCRIPTIOON OF THE DRAWINGS
FIG. 1 is a view, partly schematic, illustrating apparatus for
practice of the present invention.
FIG. 2 is an enlarged transverse cross sectional view taken in the
direction of arrows 2--2 in FIG. 1 and enlarged.
FIG. 3 is a transverse cross sectional view taken in the direction
of arrows 3--3 in FIG. 1 and enlarged.
FIG. 4 is a transverse cross sectional view taken in the direction
of arrows 4--4 in FIG. 1 and enlarged.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 illustrates a presently preferred exemplary embodiment of
apparatus 10 for practice of the invention. Apparatus 10 comprises
a catheter designated by the general reference number 12.
Associated with catheter 12 is any suitable oxygen source
designated by the general reference numeral 14.
Catheter 12 comprises a tube 16 on the distal end of which is
disposed a walled chamber 18. The opposite proximal end of tube 12
is adapted for connection with apparatus 14.
Chamber 18 is provided by a tubular element having a nominal
diameter greater than that of tube 16. FIG. 1 illustrates a
representative shape but the invention is not limited to the
particular shape or proportions illustrated. The tubular element 20
constitutes a membrane which forms chamber 18 and is fitted over
the distal end of tube 16. The opposite axial ends of element 20
are closed onto the outside of tube 16 as at 22 and 24. In this way
the chamber 18 defines an annular space 26 around the outside of
tube 16.
Tube 16 is a soft pliable material, silicone for example, which has
a circular cross sectional shape. Tube 16 is provided with a pair
of axially extending conduits, or passages, 28 and 30 respectively.
These extend the full length of the tube and the catheter includes
any suitable closure means, for example an end closure element 32
to close off the distal end of the tube for the purpose of closing
conduits 28 and 30 at that end.
Conduits 28 and 30 are communicated with the interior chamber space
26 by means of respective apertures 34 and 36 as shown in FIGS. 4
and 3 respectively. Each aperture is provided as a transversely
extending hole from the exterior of the wall of tube 16 to
intercept the corresponding conduit as shown in the drawing
figures.
In use oxygen is introduced into one of the two conduits and
conveyed through tube 16 to exit the tube at the corresponding
aperture into chamber space 26. The interior of the chamber space
is thereby perfused with oxygen. The opposite aperture provides for
return conveyance of gases via the other conduit through tube
16.
Hence, if oxygen is introduced into conduit 28, it will flow
through that conduit, exit via aperture 34 and pass into the far
distal end of chamber space 26. The flow will continue axially
through the annual chamber space 26 toward the proximal end of the
chamber to enter aperture 36 and subsequently pass via conduit 30
back through tube 16.
If the direction of flow were to be reversed, flow through chamber
space 26 would be distally, exiting tube 16 at aperture 36, passing
axially through the chamber space to re-enter tube 16 at aperture
34 for return via tube 16.
In accordance with principles of the invention, the material of
tube 20 is one which is freely permeable to gas but poorly
permeable to liquid, so that tube 20 is a membrane. A suitable
material is polydimethylsiloxane which is freely permeable to
oxygen and carbon dioxide gases. The oxygen in the catheter chamber
has a partial pressure so that oxygen can diffuse through the wall
of the chamber 18.
In use, catheter 12 is introduced into a patient such that chamber
18 is placed against the lumen of a hollow internal organ of
interest. The elongate shape illustrated in FIG. 1 is intended for
placement in the gastrointestinal tract, particularly the
intestines. The placement may be made preoperatively or
intraoperatively, and the catheter may remain in place even into a
postoperative period.
Apparatus 14 is of any suitable configuration which is capable of
perfusing oxygen through tube 16 and chamber 18 at a suitable
partial pressure. For example, the apparatus may comprise a
standard hospital oxygen supply giving a pressure of 760 mm.Hg. It
could also alternately comprise a pump which delivers
oxygen-enriched fluid. For example, the fluid may be a saline
solution which is pumped by the pump through the catheter with
provisions being made for oxygenating the saline solution prior to
introduction into the catheter so that the fluid bears a dissolved
oxygen gas at suitable partial pressure.
With the wall of chamber 18 being placed against the lumen of an
internal organ, the flow of oxygen axially along the interior of
the wall of tube 20 creates a condition whereby oxygen can diffuse
through the wall of tube 20 and into the lumen of the organ. The
diameter of chamber 26 is less than that of the organ so that the
catheter does not block flow through the tract. In this way, oxygen
may continue to be supplied to the organ so as to sustain its
vitality under conditions which otherwise might render the organ
moribund. Because the organ will also generate carbon dioxide gas
as a waste product, that waste gas can diffuse from the lumen
through the wall of tube 20 and into the fluid which is being
conveyed through chamber space 26.
The carbon dioxide gas is conveyed from chamber space 26 with the
exiting fluid flow which passes proximally through tube 16 to the
proximal end. In this way not only is oxygen made available to the
organ but a waste product from the organ is also removed.
Depending upon the degree of sophistication of apparatus 14 the
carbon dioxide may be removed from the fluid and the fluid
recirculated so as to form a closed system or otherwise the
apparatus may be an open system in which the fluid which returns
from tube 16 is discarded.
In order to sustain vitality of the intestine, the PO.sub.2 of the
oxygen introduced into chamber 26 must be high enough to create a
certain gradient cross the wall of the chamber and the lumen of the
organ. In the lumen of a healthy intestine the PO.sub.2 is about
100 mm.Hg. If the organ becomes ischemic, this figure drops to
about 60 mm.Hg. Therefore, the PO.sub.2 of the fluid delivered to
the catheter should certainly exceed 100 mm.Hg. At the present time
the use of 760 mm.Hg. oxygen gas as the sole fluid introduced into
the catheter appears to be very effective. The return flow is
merely exhausted.
The invention is also preferably practiced such that the material
of tube 20 is not significantly stretched, or expanded, when in
use, so that blockage of the passage through the tract may be
avoided.
The material of tube 20 will be permeable to molecules having
molecular weights of less than about 3000. Therefore, it is also
possible to use the catheter to introduce drugs, nutrients, and/or
other agents having molecular weights of less than about 3000.
Certain agents enhance the effectiveness of the procedure. For
example it is possible to introduce a vasodialator via the catheter
to enhance the local oxygenation. It is also contemplated that
blood or blood substitutes could be used in an oxygen-bearing fluid
to enhance the oxygen carrying capacity.
A significant advantage of the invention is that it is unnecessary
to directly involve the circulatory system for practice of the
invention. Thus, the invention is different in principle from prior
vascular oxygenation procedures which merely oxygenate the blood.
With the invention, oxygen is made available directly at the lumen
of the organ. The oxygen so delivered may be assistive of the
current vascular flow, or it may be the sole source of oxygen.
The present disclosure illustrates one preferred embodiment of the
invention in a form which is especially useful for the intestine.
Other embodiments and forms are comtemplated within the scope of
the invention. For example, the catheter could be constructed with
a full nasoanal extent through the tract with oxygen being
introduced at one end and the flow being discharged at the opposite
end.
The invention has been shown to provide for perfusion of oxygen
through a hollow internal organ of the gastrointestinal tract
independently of the vascular system. The oxygen so delivered may
be assistive of current blood flow to the organ or it may be the
sole source. While the invention may be practiced alone, it may
also be practiced in conjunction with other procedures. The
perfusion is accomplished with direct oxygen delivery to the lumen
of the organ in a controlled manner without blockage of the
tract.
* * * * *